1. Field of the Invention
This invention relates to novel forms of 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno-[2,3b][1,5] benzodiazepine (Formula A), also known as olanzapine. More specifically, the invention provides novel forms of solvate free olanzapine, methods for preparing the novel forms of olanzapine and pharmaceutical formulations containing the novel forms of olanzapine.

2. Background
As described in U.S. Pat. No. 5,736,541 (hereinafter “the '541 patent”), which is incorporated herein by reference in its entirety, the synthesis of olanzapine according to the methods described in U.S. Pat. No. 5,229,382, incorporated herein by reference in its entirety, produces a metastable, dull colored product referred to in the '541 patent as “Form I.” The '541 patent is herein incorporated by reference in its entirety. The '541 patent discloses and claims a more stable polymorphic form of olanzapine, designated as “Form II”, a method to produce “Form II” olanzapine, and pharmaceutical compositions containing “Form II” olanzapine. “Form I” and “Form II” olanzapine are characterized in the '541 patent by powder X-ray diffraction. The interplanar spacings (d-spacings) and typical relative intensities (I/I1) are reported.
U.S. Pat. No. 5,703,232 (hereinafter “the '232 patent”) claims lower alcohol solvates of olanzapine referred to in the '232 patent as “Form I” and methods for their preparation. The polymorph designated as “Form I” in the '232 patent has the same characteristic interplanar spacing by X-ray diffraction as “Form II” of the '541 patent and should thus be considered the same polymorph. Similarly, the polymorph designated as “Form II” in the '232 patent has the same characteristic interplanar spacing by X-ray diffraction as the polymorph designated as “Form I” in the '541 patent and should thus be considered the same polymorph. As used hereinafter the terms “Form I” and “Form II” refer to the olanzapine products designated as “Form I” and “Form II” in the '541 patent having the interplanar spacings and typical relative intensities shown in Table 1.
The present invention satisfies a need for additional stable, anhydrous and solvate-free polymorphic forms of olanzapine useful in the preparation of pharmaceutical formulations.